1. Field of the invention
The present invention relates to an apparatus for recording and/or playing back a magnetic tape contained in a cassette of the type known commercially as a musicassette in which the tape is wound on two coplanar spools, enclosed in a rectangular housing. The hub of each spool rotates in opposed apertures through the broad walls of the housing and is bored and internally toothed to receive a drive shaft.
Generally such cassettes are provided in the front part with reference holes through their thickness to receive positioning pins and have edge apertures through which the exposed tape can be engaged by a pressure roller and a recording and/or reading head.
2. Description of the prior art
In a known apparatus for recording and/or playing back a magnetic tape contained in a cassette, there are two capstan rollers and two pressure rollers which act selectively to transpor the tape forwards or else backwards. An actuating movable plate positions both the pressure rollers simultaneously into the proximity of the respective capstan rollers. Each one of the pressure roller can be brought into pressure contact with the corresponding capstan roller by means of a selectively controlled corresponding electromagnet.
Each of the pressure rollers is rotatably mounted between two support levers arranged parallel and pivoted on a single axis. A third lever fulcrumed on the said axis is connected elastically to the first two levers and is driven directly by the control electromagnet. Since this apparatus comprises a pair of electromagnets for the selective actuation of the pressure rollers, it is unnecessary expensive for systems wherein the magnetic tape is recorded and/or playing back only forwards.
The apparatus can incorporate an improved means for fine adjustment of the position of the recording and/or reading head.
A device is known in which the head is fixed to a base plate by screws, coaxially to each of which there is arranged a coil spring which opposes the action of the screw. Such a device has, however, the drawback of not preventing possible displacements of the recording and/or reading head in a reading head in a direction perpendicular to the screws. Furthermore, such a device turns out to be not easy to assemble because of the number of components which it uses.
There is also known another adjustment device similar to the previous one, in which a single helical spring is arranged below the recording and/or reading head in a substantially central position and is directly supported on the base blate. This device, while indeed having a simpler assembly than the previous one, does not obviate the disadvantage of not locating the head in the direction parallel to the base plate. Furthermore, such devices having a limited space for the accommodation of the spring means, the use of helical springs does not allow high spring reactions to be achieved.